Welcome to the forum @masquarat
Downgrade from 2.1.0.2 to 2.0.8.1 might help out.
Microsoft announcements might explain some of the problem:
Windows 8.1 support ended on January 10, 2023
.NET support for Windows 7 and 8.1 will end in January 2023
This Duplicati uses .NET 8. It’s possible that you’ll need to stay on .NET Framework on 2.0.8.1.